The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Thermochromatic inks are inks that change color in reaction to temperatures. They can be formulated such that they change from any color to any color, including turning from opaque or translucent colors, or turning to opaque from translucent colors, in reaction to a temperature change. They can be formulated such that they change colors at a variety of temperatures, such that a particular formulation can have several different temperature transition points or ranges, each with a particular color change from one particular color to another. They can be mixed with non-thermochromatic inks, such that blending of a constant color of the non-thermochromatic ink with the temperature-dependent color of a thermochromatic ink occurs.
Toys benefit people in both the educational process and in providing amusement. This is particularly so in the case of children, because they need stimulation to develop their minds and to expend their energy. Toys that have interesting colors or other properties can be fun or educational. For example, devices that allow one to make and show drawn images are useful as toys, as drawing tools for people of any age, and for commercial applications such as showing the day's menu in a restaurant setting. Coloring and drawing is a creative and satisfying activity for both adults and children.